The major purpose of this project is to investigate the roles of event-related brain potentials, attention and information processing and their interrelationships in the etiology, pathology and prognosis of psychiatric and neurologic disorders. Major emphasis is on the diagnostic specificity of disorders of attention and cognition and identification of the specific stage(s) of information processing underlying observed decrements in performance. Concurrently recorded event-related brain potentials and performance on cognitive tasks are used to define mechanisms of attention failure in subjects with diagnoses of schizophrenia, seizures, attention deficit disorder, learning disorders, eating disorders, dementing diseases, affective disorders, infantile autism and cerebral lesions. Biological processes influencing event-related brain potential activity are investigated by testing the effects of drugs and other treatments and by correlating these variables with biochemical measurements. Psychological correlates are investigated by relating the data to extensive neuropsychological, psychiatric and personality measures and performance on behavioral tasks.